Epigenetic phenomena are due to inheritable changes in gene expression without changes in DNA sequence or content. These are adding large complexity to the surprisingly very similar genomes of different organisms. Epigenetic phenomena include the imprinted expression of genes, i.e. in mammals only the maternally or paternally derived allele of some genes is expressed. Other examples are dosage compensation of the sex chromosomes in many organisms or position effects where the expression of a gene depends on its particular localization and neighborhood on a chromosome. On a cellular level, undifferentiated cells express different genes compared to differentiated cells. While the gene content of these cells is the same, their restricted, specialized expression pattern is inherited from one cell generation to the next with remarkable precision. It is clear that any changes in these epigenetic programs can have very severe effects on individual cells, but also organisms. This concept is emerging as one of the hallmarks of cellular transformation and tumorigenesis.
Biochemically, epigenetic processes are manifested on the level of chromatin, which is the natural "packaging" state of DNA in complex with histone proteins within a eukaryotic cell nucleus. Different DNA and histone modifications are associated with distinct functional states of chromatin and are therefore thought to direct different chromatin conformations and structures. Our research group aims to gain molecular understanding of the processes that read single and patterns of such chromatin marks and that translate these into biological function. In particular, we want to understand how chromatin marks direct the local status of chromatin and how these structures are connected to defined functional domains of chromatin as well as larger chromatin areas such as eu- and heterochromatin. To this end, we are applying a combination of biochemistry, biophysics, molecular biology and cell biology approaches.